Androxine Vortex
Archmage
Here's a good article from John Clements: Swordfighting: Not What You Think It Is
He's an expert on historically accurate medieval martial fighting, as opposed to cinematic versions of the same.
In essence, it's hard to answer your question without knowing the level of technology in your world. The level of armor technology dictates the design of swords. The design of swords, and their employment against armored opponents, dictate the styles that must be used.
Thanks for that! It was a long article so I didn't have time to read it all but it was really helpful.